AT4
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| AT4 | |
|---|---|
 M136 AT4 launcher being fired (note the large back blast, a significant problem when operating the weapon in urban environments) |
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| Type | Anti-tank |
| Place of origin | Sweden |
| Production history | |
| Manufacturer | Saab Bofors Dynamics |
| Variants | AT-4 CS |
| Specifications | |
| Weight | 6.7 kg |
| Length | 1016 mm |
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| Caliber | 84 mm |
| Muzzle velocity | 285 m/s |
| Sights | Iron sights, night vision |
- This article is about an unguided anti-tank weapon. For the Russian guided anti-tank missile, see AT-4 Spigot.
The AT4 (or AT-4) is a portable one-shot anti-tank weapon built in Sweden by Saab Bofors Dynamics (previously Bofors Anti Armour Systems). In the U.S. and NATO inventory it replaces the M72 LAW (Light Anti-armor Weapon). Saab have had considerable sales success with the AT4, making it one of the most common light anti-tank weapons in the world. It is intended to give infantry units a means to destroy or disable armored vehicles and fortifications they may encounter (though it is not generally sufficient to defeat a modern main battle tank). The launcher and projectile are manufactured pre-packed as a single unit, and the launcher is discarded after use.
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[edit] Development
The AT4 is a development of the 60 mm Pskott m/68 (Miniman), adopted by the Swedish army in 1968. Like the m/68, the AT4 was designed by Förenade fabriksverken (FFV) and manufactured at their facility at Zakrisdal, Karlstad, Sweden.
Even before the AT4 had been adopted by Sweden it participated in a competition for a new anti-tank weapon for the US Army. Runners up were the AT4 and the German Armbrust. Though impressed with the AT4, the US Army saw room for improvement - specifically the sights and slings, which were redesigned. Thereafter, the AT4 was adopted by the US army as the M136 antitank grenade launcher (LAW). The Swedish army recognised these improvements and subsequently adopted the Americanized version of the AT4 as the Pansarskott m/86 (Pskott m/86).
In the early 1990s there were tests with new 120 mm version with a tandem charge that would be able to penetrate the front armour of any modern MBT. However the project was canceled due to the dissolution of the Soviet Union and cuts in defence budget.
[edit] Operation
The AT4 operates on the principle of a "recoilless weapon," meaning that the forward inertia of the projectile is balanced by the mass of propellant gases ejecting out the rear of the barrel. Since the weapon generates almost no recoil, a relatively large projectile can be fired which would otherwise be impossible in a man-portable weapon. Additionally, since the barrel does not have to contend with the extreme pressures found in traditional guns, it can be designed to be very lightweight. The disadvantage of this design is that it creates a large "back-blast" area behind the weapon which can cause severe burns and pressure injuries - both to friendly personnel in the vicinity of the user and, in some cases, to the user himself. This makes it difficult to employ in confined areas.
To fire, the user must first ensure that no friendly troops or equipment are present in the backblast area. If firing from the prone, (i.e. lying on his stomach) he must also place his legs well to the side to avoid burning himself. He then disengages two safeties, cocks a mechanical firing pin and presses a trigger button. Aiming is accomplished via range-adjustable plastic sights, which are concealed beneath sliding covers for transport. Alternatively, the weapon can carry an optical night-sight on a removable mount. The AT4 requires little training and is quite simple to utilize, making it suitable for general issue. Because the expensive unit cost is prohibitive to regular live-fire training, practice versions exist which are identical in operation but fire reloadable 9mm or 20mm tracers. The 20mm version is also a recoilless weapon and is favored by the Swedish army because of the added realism of the back-blast as compared to the "plonk" sound of the 9mm round (very similar to tapping your finger on an empty can).
[edit] Specifications
- Length: 101.6 cm (40 in.)
- Weight: 6.7 kg (14.75 pounds)
- Bore diameter: 84 mm
- Maximum effective range: 300 metres (984.3 feet)although it has been used in excess of 500 meters for area effect.
- Penetration: 400 mm of rolled homogeneous armour (also see below)
- Time of Flight (to 250 metres): less than 1 second
- Muzzle velocity: 285 metres (950 feet) per second
- Operating temperature: -40 to +60° C (-40 to +140° F)
- Ammunition: Fin-stabilized projectile with shaped charge warhead
[edit] Projectiles
There are several different projectiles for the AT4. Note that since the AT4 is a one-shot weapon, these projectiles are preloaded.
[edit] HEAT (High Explosive Anti Tank)
The AT4 HEAT is a low-trajectory, low-dispersion weapon that can penetrate up to 420 mm of armor.
[edit] HEDP (High Explosive Dual Purpose)
For use with bunkers and buildings. The projectile can be set to detonate on impact or with a delayed detonation.
[edit] HP (High Penetration)
Extra high penetration ability. Can penetrate 500 to 600 mm armour.
[edit] AT4 CS
The AT4 CS (Confined Space) is a variant of the AT4 specially designed for urban warfare.
The regular AT4 can be extremely dangerous to fire from confined spaces due to the extreme increase in pressure. The back flame can also bounce back at the soldier if there is a wall or another solid object within 15 metres of the breech. The "CS" version utilizes a liquid countermass (specifically salt water) ejected from the rear upon firing, which neutralizes some of the backblast. While the CS is considerably safer than the regular AT4, there have still been reports of soldiers fainting when firing the AT4 CS from confined spaces. The AT4 CS was recently featured on the Discovery Channel show Futureweapons.
[edit] Operators
Brazil used in Brazilian Army
France
Ireland, designated SRAAW in the Irish Defence Forces.
Lithuania
Netherlands
Sweden, designated Pansarskott m/86 (AT4, all versions) and used by all branches of the Swedish Armed Forces.
Republic of China (Taiwan)
United Kingdom, designated L2A1 (ILAW) (AT4 CS with high penetration warhead), used by the British Army. [1]
United States, designated M136 AT4 in USMC and United States Army service.
Chile
Venezuela
Denmark
